Medical Imaging Test 3
What is required for an analog image intensifier to produce a digital image? a. CCD c. DICOM b. PACs d. LAN
a. CCD
A series of tissue density values that evolved for CT measurements is called ____ units. a. Hounsfield c. attenuation b. H & D d. iterative
a. Hounsfield
A ____ artifact is caused by attenuation of the beam as it passes through the patient. a. beam-hardening c. star b. ring d. streak
a. beam-hardening
The RF signal strength determines a. brightness. c. section thickness. b. field strength. d. spatial resolution.
a. brightness.
The ____ is how well the detectors receive photons from the patient. a. capture efficiency c. conversion efficiency b. absorption efficiency d. response time
a. capture efficiency
If a piece of equipment, object, or device is to be used for a MR procedure, it is important to a. check its labeling by the ASTM Standard F2503. b. check it first with a small personal magnet before using it in the scan room. c. contact the MR vendor to check compatibility with the scanner. d. bring it into the scan room prior to the patient's entry, to check its safety.
a. check its labeling by the ASTM Standard F2503.
The process of modifying pixel values by a mathematical formula is called a. convolution. c. calculus. b. deconvolution. d. interpolation.
a. convolution.
First-generation CT scanners scanned the ____ only. a. head c. abdomen b. thorax d. pelvis
a. head
The CTDI dose measurement a. is slice-based. b. takes into account the total amount of irradiated tissue. c. represents the average total dose to the patient during the examination. d. measures entrance skin exposure (ESE).
a. is slice-based.
The source of magnetic fields within the body a. is the spinning nucleus of an atom. b. are the neutrons. c. are the stationary electrons. d. all of the above
a. is the spinning nucleus of an atom.
The CT radiographer usually varies the ____ to control the primary beam. a. mA c. kVp b. time d. distance
a. mA
Protons will alternate from a. parallel to antiparallel. b. parallel to neutral. c. perpendicular to positive. d. positive to negative.
a. parallel to antiparallel.
The pressure of a contrast medium injector is measured in a. pounds per square inch. c. force per density. b. pounds per cubic centimeter. d. viscosity per square inch.
a. pounds per square inch.
The rotation of the axis of rotation is termed a. precession. c. nuclear orientation. b. rerotation. d. frequency.
a. precession.
The MHz frequency magnetic field for MRI is produced by a/an a. radio transmitter coil. c. digital converter. b. optical cable. d. none of the above
a. radio transmitter coil.
When gradient coils are referred to, the z axis coil is referred to as the ____ gradient. a. selection c. frequency encoding b. phase encoding d. none of the above
a. selection
The amount of heat load an anode can tolerate for a sequence of exposures is known as a. short-term loading ability. c. tube-rate loading ability. b. continuous heat-loading ability. d. dose-dependent loading.
a. short-term loading ability.
The quantity of resonating spins in a tissue expressed as a percentage of the proton density of water is a. spin density (). c. echo time (TE). b. repetition time (TR). d. inversion time (TI).
a. spin density ().
Each of the following is an example of an RF pulse sequence EXCEPT a. stationary. c. gradient. b. spin-echo. d. inversion recovery.
a. stationary.
The basic principle of MR physics involves an established relationship between an external magnetic field and the gyromagnetic ratio of an atom. This is expressed as the a. inverse square law. b. Larmor equation. c. Hounsfield coefficient. d. H & D curve.
b. Larmor equation.
In the event a CT patient needs emotional support for a procedure, during the acquisition a. patient restraints should be used. b. a patient family member should be allowed to attend to the patient. c. the department nurse should be asked to attend to the patient. d. the CT supervisor should stand by the patient.
b. a patient family member should be allowed to attend to the patient.
The ____ is how well the detectors convert incoming photons. a. capture efficiency c. conversion efficiency b. absorption efficiency d. response time
b. absorption efficiency
In order to perform digital subtraction angiography, a. a mask image is acquired after injection. b. bony anatomy is eliminated from the final image. c. patient motion is not a concern, as this is a post-processing function. d. the injection image is acquired before the scout image is taken and then subtracted from the other.
b. bony anatomy is eliminated from the final image.
The actual response of proton spin to an RF pulse is to a. change the magnetic moment in a recovery circular motion. b. change the magnetic moment in a precessing corkscrew motion. c. remain stationary. d. change the magnetic moment in a precessing circular motion.
b. change the magnetic moment in a precessing corkscrew motion.
The amount of heat an anode can tolerate during a fluoroscopic exposure is known as ____ loading ability. a. short-term c. pulsed fluoro b. continuous-heat d. intermittent fluoro
b. continuous-heat
What type of image acquisition is used when eliminating bone and soft tissue structures from an image so that only contrast-filled vessels remain? a. digital angiography b. digital subtraction angiography c. digital cineradiography d. image reversal angiography
b. digital subtraction angiography
Vascular imaging using angiography requires a. single-phase input and three-phase output. b. generators with 1 ms interrogation and forced extinction times. c. C-arm rotational capability during image acquisition. d. 500 kHU x-ray tubes at a minimum.
b. generators with 1 ms interrogation and forced extinction times.
The most recent generation of CT scanners use a ____ motion. a. translate-rotate c. linear b. helical d. elliptical
b. helical
In a MR gantry, the patient lies at a. the lowest gantry level. c. geometric center. b. isocenter. d. the center of the external coils.
b. isocenter.
The contrast medium warming device on the pressure injector is intended to a. bring the contrast medium to room temperature. b. maintain the temperature of the contrast medium. c. bring the contrast medium to body temperature. d. increase contrast viscosity through warming.
b. maintain the temperature of the contrast medium.
When gradient coils are referred to, the y axis coil is referred to as the ____ gradient. a. selection c. frequency encoding b. phase encoding d. none of the above
b. phase encoding
The Larmor frequency is the ____ frequency. a. quantum c. linear b. precessional d. all of the above
b. precessional
Contemporary CT scanners use solid state detectors. These detectors utilize a. sodium iodide crystals. c. xenon gas. b. rare earth ceramic scintillators. d. freon gas.
b. rare earth ceramic scintillators.
The time interval between pulse sequences is a. spin density (). c. echo time (TE). b. repetition time (TR). d. inversion time (TI).
b. repetition time (TR)
A ____ artifact is caused by detector error. a. beam-hardening c. star b. ring d. streak
b. ring
Before performing an MR scan on a patient with compromised renal function, a. the patient should be NPO for 24 hours. b. the patient's GFR should be assessed. c. an IVU should be performed. d. an ultrasound study of the kidneys should be done.
b. the patient's GFR should be assessed.
Superconductive magnets used in MR are characterized by a. field strengths of .2T-.35T. b. the use of liquid helium as a cryogen. c. resistive magnets with vertical fields. d. the ability to turn the magnetic field on and off at will.
b. the use of liquid helium as a cryogen.
CT image data is acquired in the a. coronal plane and reconstructed in the axial plane . b. transverse plane and reconstructed in any plane. c. sagittal plane . d. axial plane and reconstructed in the coronal plane.
b. transverse plane and reconstructed in any plane.
The combination of field of view (FoV), acquisition matrix, and slice thickness determines the MR data element known as a a. pixel. c. byte. b. voxel. d. magnetic moment.
b. voxel.
The range of CT numbers or Hounsfield Units varies from a. 100 to 300. c. -1000 to +3000. b. -100 to +300. d. 1000 to +3000.
c. -1000 to +3000.
Most angiographic studies are produced at what kVp range? a. 30 to 40 c. 50 to 100 b. 40 to 50 d. 75 to 110
c. 50 to 100
Digital image receptors used in angiography a. require a CCD for image capture. b. are composed of selenium detector material. c. acquire the images digitally in the detector material. d. permit post-processing of images, unlike analog image intensifier detectors.
c. acquire the images digitally in the detector material.
CT scan pitch uses all of the following technical parameters EXCEPT a. slice thickness. c. acquisition mAs . b. 360-degree gantry rotation. d. table increment.
c. acquisition mAs
The calculation of CT numbers is based upon the calculation of a. half-value layers. c. attenuation coefficients. b. half-lives. d. pitch.
c. attenuation coefficients.
The process of combining detector elements into various combinations in order set slice thickness is called detector a. modulation. c. binning. b. dose efficiency. d. interpolation.
c. binning.
Which of the following will permit a greater volume of contrast injection per unit of time? a. lower psi injection rates b. longer catheter lengths c. catheter side-holes d. higher viscosity of contrast media
c. catheter side-holes
With MSCT scanners, resolution is primarily determined by a. prepatient collimation. b. dose. c. collimation at the detector. d. gantry rotation speed.
c. collimation at the detector.
The ____ is determined by how well the detector converts the absorbed photon information to a digital signal for the computer. a. capture efficiency c. conversion efficiency b. absorption efficiency d. response time
c. conversion efficiency
What type of image acquisition is used mainly for cardiac catheterization? a. digital angiography b. digital subtraction angiography c. digital cineradiography d. cineangiographic imaging
c. digital cineradiography
The time between a 90-degree pulse and the echo during a spin-echo pulse sequence is a. spin density (). c. echo time (TE). b. repetition time (TR). d. inversion time (TI).
c. echo time (TE).
The most widely used technique for MR image reconstruction is a. back projection. b. interpolation. c. fast Fourier transformation (FFT). d. Larmor equation precession (LEP).
c. fast Fourier transformation (FFT).
When gradient coils are referred to, the x axis coil is referred to as the ____ gradient. a. selection c. frequency encoding b. phase encoding d. none of the above
c. frequency encoding
Contrast-enhanced MR images use ________as the contrast material of choice. a. iodine c. gadolinium b. barium d. hydrogen
c. gadolinium
The characteristic MR noise that is uncomfortable for patients and staff is due the ________ turning on and off at a high frequency. a. external magnet c. gradient coils b. external coils d. RF coil
c. gradient coils
The gyromagnetic ratio is the ratio of the magnetic a. moment to the moment of magnetic force. b. force to the moment of inertia. c. moment to the moment of inertia. d. none of the above
c. moment to the moment of inertia.
To achieve coronal or sagittal sections, a. the gantry is repositioned. b. the patient is repositioned. c. reconfiguration software is implemented. d. none of the above
c. reconfiguration software is implemented.
The localization image produced by the CT scanner is technically called a/an a. volume rendered image. c. scanogram. b. scout film. d. FOV image.
c. scanogram.
The size of the tissue voxel determines a. brightness. c. section thickness. b. field strength. d. spatial resolution.
c. section thickness.
The primary variable in the data collection procedure during MRI is the a. repeats. c. sequence of RF pulses. b. stationary magnet. d. all of the above
c. sequence of RF pulses.
A ____ artifact is caused by the presence of metal in the patient. a. beam-hardening c. star b. ring d. streak
c. star
Which can serve as both the transmitter and receiver of the MRI signal? a. the stationary magnet c. the RF coils b. the gradient coils d. the cryogen coils
c. the RF coils
To produce magnetic field gradients in MRI, electromagnetic coils are oriented in a. one dimension. c. three dimensions. b. two dimensions. d. four dimensions.
c. three dimensions.
The gantry of the CT unit contains the a. post-processing workstation. c. x-ray tube. b. operator's interface. d. all of the above
c. x-ray tube
Vascular imaging generators should have the capacity to deliver ____ mA. a. 50 c. 300 b. 100 d. 1,000
d. 1,000
The primary mathematical method used in the creation of computerized medical images is the ____ transformation. a. interpolation c. algorithm b. Hounsfield d. Fourier
d. Fourier
Select the TRUE statement from the choices below. a. Extinction time is the time required to prepare the x-ray tube for exposure. b. Window level adjusts the contrast and window width adjusts the density of an image. c. The flow rate is the rate at which the contrast medium is filtered by the kidneys. d. The typical design of the vascular imaging system uses a C-arm configuration.
d. The typical design of the vascular imaging system uses a C-arm configuration.
Computed tomography sections are available as a. coronal. c. sagittal. b. transverse. d. all of the above
d. all of the above
Higher field strength MRI magnets permit a. shorter scan times. c. stronger signal strength. b. better resolution. d. all of the above
d. all of the above
MRI has been achieved with ____ magnets. a. resistive c. superconductive b. permanent d. all of the above
d. all of the above
MSCT scanners have evolved greatly over the last few years, particularly with regard to slice combinations, scanning speed, and clinical utility. As these scanners gather more slices of data per rotation, a major technological challenge is a. the amount of data handled by the computer. b. the number of images to be analyzed by the clinician. c. developing technologies to minimize dose. d. all of the above
d. all of the above
Modern pulsed CT scanners operate at a. 120 kVp. c. up to 1,000 mA. b. 1 to 5 msec. pulses. d. all of the above
d. all of the above
Patient precautions with MR scanning include a. claustrophobia. b. not touching the inside of the gantry during scanning. c. ferromagnetic implants or prosthetic devices. d. all of the above
d. all of the above
Quality control programs in the vascular imaging laboratory require a. a close relationship with the equipment vendor. b. periodic monitoring of viewing systems such as video monitors. c. in-house biomedical engineers working at a "first-line " level supported by the vendor. d. all of the above
d. all of the above
The CT console provides the radiographer access to a. the software program. c. data display. b. data acquisition. d. all of the above
d. all of the above
The CT radiation beam is collimated a. at the tube exit. c. pre-patient and post-patient. b. at the detector entrance. d. all of the above
d. all of the above
The CT table is a. made of carbon graphite. c. motor-driven. b. rated for maximum weight. d. all of the above
d. all of the above
The gradient coils determine the a. section thickness. c. plane of the image. b. resolution. d. all of the above
d. all of the above
The heat-loading capacity of an x-ray tube depends on a. focal spot size. c. generator configuration. b. anode angle. d. all of the above
d. all of the above
The most common variable in operating an MRI unit is the ____ used to enhance image quality. a. TI c. TR b. TE d. all of the above
d. all of the above
The resolution of the CT image depends on the a. pixel. c. matrix size. b. voxel. d. all of the above
d. all of the above
The smaller the scan field size, the a. better the resolution. c. less the risk of motion. b. faster the scan time. d. all of the above
d. all of the above
The strength of a MR signal is a. directly proportional to the strength of the magnetic filed. b. directly proportional to the strength of BO. c. directly related to the tesla of the magnet. d. all of the above
d. all of the above
X-ray tubes used in vascular interventional procedures a. require mega heat unit tubes. b. have graphite-backed anodes for heat tolerance. c. have a larger anode disk diameter and thickness. d. all of the above
d. all of the above
As noise increases in a CT image, a. low contrast resolution increases. c. low contrast resolution decreases. b. dose to the patient increases.d. both a and c
d. both a and c
To prevent extraneous RF signals from degrading MR image quality, MR scan suites are enclosed in a a. copper cage. c. Faraday cage. b. steel cage. d. both a and c
d. both a and c
In MRI, the primary visual factor is often called a. linearity. c. resolution. b. geometric shape. d. brightness.
d. brightness.
Of the choices below, the preferred method for angiographic image acquisition is a. roll film changer because of speed. b. cut film changer because of film-screen contact. c. cineangiographic camera because of high frame rates and low dose. d. digital imaging technology because of post-processing functionality.
d. digital imaging technology because of post-processing functionality.
Which type of generator is typically chosen for use during cardiovascular and interventional angiographic procedures? a. single-phase c. three-phase, 12-pulse b. three-phase, 6-pulse d. high frequency
d. high frequency
The time between a 180-degree pulse and a 90-degree inversion pulse in an inversion recovery pulse system is a. spin density (). c. echo time (TE). b. repetition time (TR). d. inversion time (TI).
d. inversion time (TI).
In order to create a more homogenous magnetic field in MR, ______ is required. a. a radio frequency c. an autotransformer b. a k-space coil d. shimming
d. shimming
The time required after precessing spins have aligned at an angle to the external field due to an RF pulse losing 63% of their coherence is a. spin density (). c. echo time (TE). b. spin-spin relaxation time (T2). d. spin-lattice relaxation time (T1).
d. spin-lattice relaxation time (T1).
The time required for precessing spins to align with the constant external field to 63% of the maximum possible strength is a. spin density (). c. echo time (TE). b. repetition time (TR). d. spin-lattice relaxation time (T1).
d. spin-lattice relaxation time (T1).
A ____ artifact is caused by motion. a. beam-hardening c. star b. ring d. streak
d. streak